Cyclohexanone is a commercially important starting compound for the production of caprolactam. The production of cyclohexanone typically involves the oxidation of cyclohexane which yields cyclohexanol and cyclohexanone as the principal oxidation products. (See, U.S. Pat. No. 3,946,076, the entire content of which is expressly incorporated hereinto by reference). The production process also generates substantial quantities of by-products which have higher boiling points than cyclohexanone.
It has been proposed in the past that some of these by-products of cyclohexanone production, especially multi-cyclic ketones, can be thermally cracked into cyclohexanone and cyclohexanol. (See, U.S. Pat. No. 4,173,586, the entire content of which is incorporated hereinto expressly by reference.) It is also known that cyclohexanediols can be catalytically cracked at elevated temperatures and pressures to produce cyclohexanone and cyclohexanol. (See, U.S. Pat. No. 5,874,651, the entire content of which is incorporated hereinto expressly by reference.)
It has now been discovered that organic by-products having higher boiling points than cyclohexanone (usually obtained from the bottoms of a distillation operation to separate cyclohexanone from other reaction products during cyclohexanone production) can be converted to recoverable cyclohexanone and cyclohexanol using a catalyst having high aluminum oxide concentrations.
These, and other, aspects and advantages will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.